No power to subwoofer

[asteve33]

2003 LX 470 Mark Levinson

Wires to rear subwoofer get no power
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Update: Subwoofer itself was the issue. I checked the speaker’s resistance using a multimeter. If it works, you should be seeing 4ohms. I bought a Skar Audio EVL-65 D4 6.5"and it works now. I used pliers to break up the checker pattern back of the sub box to make a bit more room for it.
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Symptoms:
All 4 door speakers, radio and nav work properly
The amp (passenger seat) gets power, fan spins. Blue/yellow wire at amp shows 14 volts
wires (blue/white & blue/black) at rear sub show 0 volts
the same wires show 0 volts at the amp itself

What I’ve checked:
The AMP fuse (engine bay)

Do I just need a new amp? Or to send the amp in for repair?

 

[jaewastooshort]

This might be a difficult reach, but I would think the appropriate test on the speaker signal wires would be to test continuity between the amp connector and the subwoofer connector. If the wiring continuity is good, next what you're trying to figure out is if the amplifier is sending an output signal. I would not expect to see voltage on the speaker wires when the stereo is not actively trying to send a signal to the speakers. You might see voltage if the stereo is on and sending signal, but I'm not sure what would be normal when audio signal is sent.

This is a link I found and cannot vouch for, but it might provide a starting point on measuring the amp output to the sub at the amp output connector and at the speaker input connector.

 

[dsmartinjr]

Did you ever find the source of your power problem? I am having the same issue: no output to the subwoofer.

 

[asteve33]

Did you ever find the source of your power problem? I am having the same issue: no output to the subwoofer.

Not yet. I bought a new amp recently. Just plugged it in and same issue no power to rear speaker but all other speakers work. I’ll lyk if I figure it out

 

[asteve33]

This might be a difficult reach, but I would think the appropriate test on the speaker signal wires would be to test continuity between the amp connector and the subwoofer connector. If the wiring continuity is good, next what you're trying to figure out is if the amplifier is sending an output signal. I would not expect to see voltage on the speaker wires when the stereo is not actively trying to send a signal to the speakers. You might see voltage if the stereo is on and sending signal, but I'm not sure what would be normal when audio signal is sent.

This is a link I found and cannot vouch for, but it might provide a starting point on measuring the amp output to the sub at the amp output connector and at the speaker input connector.

I tested for continuity between the 4 blue wires that run from under the front passenger seat to the rear speaker. I confirmed there is continuity. For whatever reason the amp isn’t sending power to the sub though. I bought a refurbed amp from a oemautopartz (eBay) and unfortunately, same issue with the new amp

 

[asteve33]

Did you ever find the source of your power problem? I am having the same issue: no output to the subwoofer.

Subwoofer itself was the issue. I checked the speaker’s resistance using a multimeter. If it works, you should be seeing 4ohms. I bought a Skar Audio EVL-65 D4 6.5"and it works now. I used pliers to break up the checker pattern back of the sub box to make a bit more room for it.